1. Field of the Invention
The present invention relates to chip bonding, and more particularly, to a chip bonding tool, a chip bonding apparatus having the same, and a method thereof, capable of preventing contamination of the chip bonding tool due to an adhesive agent during a chip bonding process for adhering a semiconductor chip to a substrate using a laser beam.
2. Description of the Related Art
Generally, a semiconductor package is assembled by various mounting methods. In recent times, with miniaturization and high integration of products, high performance of semiconductor chips is required, and thus the number of pins should be increased. This requires further improvement of reducing the distance between pins (i.e., a pad pitch). A flip chip bonding technology has been developed in order to meet this requirement.
In this flip chip bonding technology, as an adhesive resin for adhering a semiconductor chip to a substrate and preventing intrusion of foreign substances, an anisotropic conductive film (ACF), an anisotropic conductive adhesive (ACA), a non-conductive polymer (NCP), or the like is widely used.
As described above, when two media are bonded to each other using ACF, ACA, or NCP, a method of thermally bonding the media by pressing the media with a constant temperature, pressure and time is used, in consideration of characteristics of the bonding media.
A method of heating the media with a constant temperature may include using a hot bar with a heater (a hot-press method), using friction heat of contact parts using ultrasonic waves (an ultrasonic method), using a laser (a laser method), or the like.
The laser method uses a laser beam as a heat source; the beam passes through a transparent window while constant pressure is applied to the semiconductor chip and substrate.
Korean Laid-open Patent No. 2005-0123395 discloses a flip chip bonding apparatus using a laser beam, which will be described below in brief.
Referring to FIGS. 1 and 2, a substrate 3 applied with an adhesive agent 3a is disposed on a stage 2, and a semiconductor chip 6 is sucked to a lower surface of a suction block 5 by a semiconductor chip suction part 4.
In this state, the suction block 5, which sucks the semiconductor chip 6, is moved downward such that a connection terminal 7 of the semiconductor chip 6 is in contact with a connection terminal 8 of the substrate 3. As a result, the semiconductor chip 6 is pressed downward and a laser beam 9 transmits through the suction block 5 formed of a transparent material.
At this time, the adhesive agent 3a applied to the substrate 3 is spread around the semiconductor chip 6 by heat of the laser beam 9 and then cured.
However, in the conventional flip chip bonding apparatus using a laser beam, the adhesive agent 3a may not be partially spread around the semiconductor chip 6 during the flip chip bonding process and then instantly cured so that the cured part can project higher than the semiconductor chip 6.
Such a problem may be caused by incorrect adjustment of the ACF, ACP or NCP, and may result in contamination of the chip bonding tool by the adhesive agent.
Such contamination may cause serious damage to the semiconductor chip or the press structure as the bonding process is performed and the adhesive agent is cured. In particular, in the case of the flip chip bonding apparatus using a laser beam, since the suction block is formed of a transparent material for transmitting a laser beam, it is impossible to continuously perform the bonding process when the contamination is generated. Such a phenomenon is likely to be generated when a width D1 of the suction block is greater than a diameter D2 of the semiconductor chip.
That is, in the case of the conventional flip chip bonding apparatus using a laser beam, the width D1 of the suction block is greater than the diameter D2 of the semiconductor chip, and the suction block is formed of a transparent material in order to uniformly radiate the laser beam 9 onto the entire surface of the semiconductor chip 6.
However, when the width D1 of the suction block is greater than the diameter D2 of the semiconductor chip, the adhesive agent 3a may contaminate the suction block 5 during the flip chip bonding process. As described above, when the suction block 5 is contaminated, transmissivity of the laser beam 9 may abruptly decrease, thereby causing delay or disruption of the flip chip bonding process.